Explosively-formed electrical connection



Sept. 12, 1967 W F. BROSKE EXPLOSIVELY-FORMED ELECTRICAL CONNECTION 4Sheets-Sheet 1 Filed May 14, 1965 INVENTOR. WILLIAM F BROSK L Sept. 12,1967 w. F. BROSKE EXPLOSIVELY-FORMED ELECTRICAL CONNECTION 4Sheets-Sheet 2 Filed May 14, 1965 viii .v M mo 35:

W m m R 3 Fl- I m M N Y B urrm E Sept. 12, 1967 w. F. BROSKEEXPLOSIVELY-FORMED ELECTRICAL CONNECTION Filed May 14, 1965 INVENTOR.WILLIAM FBROSKE BY 60.14 h w -fi Sept. 12, 1967 w. F. BROSKEEXPLOSIVELY-FORMED ELECTRICAL CONNECTION United States Patent 3,341,650EXPLOSIVELY-FORMED ELECTRICAL CONNECTION William F. Broslre, Camp Hill,Pa., asslgnor to AMP Incorporated, Harrisburg, Pa. Filed May 14, 1965,Ser. No. 455,818 8 Claims. (Cl. 174-94) This constitutes acontinuation-in-part application of my prior application, Ser. No.424,041, filed Jan. 7, 1965, now abandoned.

The art of joining electrical conductors requires a secure connectionthat will withstand vibration, corrosion, tensile failure, andconcurrently provide a low millivolt drop through the connection. Theart of joining electrical utility conductors is further complicated bythe large sizes of the conductors (e.g., 4/0 and larger), as well as thefact that the connections are made at remote locations where auxiliarypower is not available. Additionally, these connections must withstandthe elements with a life expectancy of at least twenty years.

In view of these requirements, a suitable way of coldforging aconnection onto a pair of utility wires is accomplished by theapplication of energy generated by an explosive. It is an object of thisinvention to provide an explosively-powered means for splicinglarge-sized wires with ease of operation and concomitant excellence ofthe comiection.

It is also an object of this invention to provide such a connection thatis easily applied and available at a very reasonable cost.

It is also an object of this invention to cold-forge a connection ontoaluminum-stranded wire having a steel reinforcing means, whereby theconnector is deformed onto the steel strand as well as onto the aluminumstrands.

Other objects and attainments of the present invention will becomeapparent to those skilled in the art upon a reading of the followingdetailed description when taken in conjunction with the drawings inwhich there are shown and described illustrative embodiments of theinvention; it is to be understood, however, that these embodiments arenot intended to be exhaustive nor limiting of the inventionbut are givenfor purposes of illustration in order that others skilled in the art mayfully understand the invention and the principles thereof and the mannerof applying it in practical use so that they may modify it in variousforms, each as may be best suited to the conditions of a particular use.

In the drawings:

- FIGURE 1 is an exploded view illustrating the various components of aconnector embodying the principles of this invention;

FIGURE 2 is a perspective view, partially broken away, showing thedevice of FIGURE 1 in assembled condition;

FIGURE 3 is a sectional view showing the device of FIGURES 1 and 2 priorto application;

FIGURE 4 is a view similar to FIGURE 3 showing the device afterapplication;

FIGURE 5 is a perspective view of another embodiment of a tool forcontaining a connector during the assembly cycle;

FIGURE 6 is a sectional view taken through plane 66 of FIGURE 5;

FIGURE 7 is a sectional view of another embodiment of a connectoremploying the principles of the invention in (assembled condition priorto being secured to the wire; an

FIGURE 8 is a view similar to FIGURE 7 illustrating the device afterapplication.

As shown in FIGURE 1, the central connecting memice ber, generallyindicated A, includes a ferrule-shaped member having a central section10- of reduced diameter which flares into a pair of conductor-receivingsections 12 and 14 of a greater diameter. The conductor-receiving member12 has a tapered outer surface 1 6 at its mouth 18. Theconductor-receiving member 14 has a similar tapered outer surface 20 atits mouth 22. The inner diameters of members 12 and 14 are adapted toreceive (FIGURE 3) a pair of wires W, W, respectively.

A solid rod 24 (FIGURE 1) is inserted into the central portion 10 of theconnecting member A. This rod is approximately the same length as thecentral section 10.

A die member 30 (FIGURE 1) is formed in two parts, 32 and 34, which,when joined together, complement each other to form a right-circularcylinder. These die members have tapered outer surfaces 36 (FIGURE 3).As shown in FIGURE 1, the outer edges of the die half 32 include aseries of projections 38 with corresponding indentations therebetween.The projections and indentations are designed so that the projections onone half are offset with the indentations on the other half. Afriction-fit be tween the projection and the indentation permits thedies to be assembled, forming the cylindrical member 30; the other diebeing identical except that it tapers in the opposite direction. Thesedies may be made out of a suitable metal, or even a sufficiently stiffplastic such as Lexan or Synthane.

A series of seals 40 are also constructed as split rings for ease ofassembly. A pair of these seals is fitted around the central section 10of the connecting member A on each side of an explosive charge Badjacent the untapered portion of each of the dies 30. These seals arefor the purpose of confining the gas generated during the explo sivecycle and may be made out of linear polyethylene. The split sections ofthe seals are misaligned to lessen the possibility of gas blowout.

A cylindrically-shaped, cushioning device 42, 42' is inserted aroundeach open end of the conductor-receiving members 12 and 14. As shown inFIGURE 3, these cushioning devices are tapered on their inside surfacesto match the corresponding surfaces 116 and 18 on the outer surfaces ofthe conductor-receiving members.

The powder charge B is contained between the gas seals 40 and may beeither a molded charge or a quantity of granulated explosive powdersproperly held in position. One means of retaining the entire assembly inoperating condition includes a tubular, stiff, paper cylinder 44 ofsufficient length to encompass all the components. The outer ends of thecylinder are turned over (FIGURE 2) to retain the parts in assembledcondition.

The device may be inserted into any suitable chamber capable ofpermitting detonation. The chamber, shown in FIGURES 3 and 4, includes apair of identical connectorreceiving portions 50 and 52. These sectionsmay be made of cold-rolled steel and bolted together to retain theconnector therein. A pair of tapered apertures 54, 56 permits insertionof the wires W, W during the connecting cycle. A minor aperture 58 inone of the sections permits insertlon of a detonator (e.g., electricalmatch) for access to powder charge B.

Another embodiment of the invention is shown in FIG- URES 7 and 8. Inthis embodiment, means is provided for gripping the steel strands S, S.The device illustrated in FIGURES 7 and 8 is similar in most respects tothe de vice shown in FIGURES l-4. It includes a connector A comprised ofa central section 110, and conductor-receivmg sections 112 and 114having tapered surfaces 116 and 120 at the respective mouths 118 and122. A solid rod 124 is disposed within the central section 110.

A pair of collars 126 and 128 are also disposed within the connector A.As shown in FIGURE 7, the collars are concentric with the connector A,with one of the collars disposed on each side of the central rod 124.The collars 126 and 128 have an outside diameter slightly smaller thanthe inside diameter of the conductor-receiving sections 112 and 114 toprovide an interference fit. Alternatively, the collars 126, 128 and thecentral rod 124 could be made integral. In the event that they are madeintegral, the outer tube of the connector A may be made of constantdiameters and the central section reduced in diameter after the integralmember is inserted. It is noted that the central aperture of the collars126 are of sufficient diameter to accommodate the steel strands S, S.

Another embodiment of a device for containing the wires, connector andpowder charge is shown in FIG- URES 5 and 6. A chamber havingcomplementary connector-receiving portions 60 and 62 is secured alongone edge of these portions by pivot pin 64 which passes throughpiano-hinge portions 66, 66. The opposite edge of each portion hasU-shaped recesses 70, 70. A series of handles are threadedly connectedto pivoted rods 74 in the U-shaped recesses of connector-receivingportion 62.

The connector-receiving portions 60 and 62 may be closed (FIGURE 6) toencompass the connector and wires in the same manner as the device shownin FIG- URES 3 and 4. The rods 74 are pivoted into the recesses 70, andthe handles 72 are tightened to firmly secure the portions 60 and 62together.

0peratz'on.When it is desired to splice a pair of wires W, W, theconnector is assembled in the manner illustrated in FIGURE 3. Theconnector is retained in the tool sections 50, 52, with the wiresextending through the apertures 54, 56. The tool is bolted together andan electric match inserted into the aperture 58. Excitation of theelectric match by standard voltage causes it to ignite, therebydetonating the powder charge B.

Detonation of the powder drives the dies 30 outwardly and causescold-forging of the ferrule portions 12 and 14 onto the wires W, W. Theresistance of the metal to cold-forging reduces the speed of the dies asthey travel outwardly. At their outer limits, the dies meet with furtherresistance when they contact cushioning members 42, 42'. Longitudinaldeformation of these cushioning members prevents further travel of thedies 30. The tool may then be unbolted and a secure electricalconnection is formed.

It is noted that between forty and fifty grains of Bulls Eye or Uniquepowder may be used in connecting 4/0 ACSR wires to each other. Theconnecting member A may be made of aluminum.

The embodiment shown in FIGURES 7 and 8 is, in most respects, identicalwith the embodiment of FIG- URES 1-4. However, in preparing the wires W,W, the outer strands are stripped back to expose the central steelstrands S, S. When positioning the wires W, W in the connector A, thecentral steel strand S is positioned within the collar 126, with the endof the other strands of the wire W abutting the collar .8. The wire W isinserted in the opposite end of the connector in the same manner.

In operation, the actuation of dies 132 (in the same manner as theprevious embodiment) compresses the collars 126, 128 onto the steelstrands S, S, respectively, and concurrently the outer sections 112, 114of the metallic tube onto the collars 126, 128. Since the strongeststrand of the wires is directly secured to the connector, the tensilestrength of the connection is increased.

Changes in construction will occur to those skilled in the art andvarious apparently different modifications and embodiments may be madewithout departing from the scope of the invention. The matter set forthin the foregoing description and accompanying drawings is offered by wayof illustration only. The actual scope of the invention is intended tobe defined in the following claims when viewed in their properperspective against the prior art.

I claim:

1. A connector for splicing conductors comprising: a ferrule adapted toreceive an electrical conductor, an explosive charge surrounding theouter surface of the central portion of the ferrule, means disposed onsaid ferrule actuated by the explosive charge for cold-forging theferrule to the conductor.

2. An electrical connector for splicing an electrical conductorcomprising: a ferrule adapted to receive a conductor therein, anexplosive charge located on and surrounding the outside surface of thecentral portion of the ferrule, a first cylindrically-shaped diesurrounding said ferrule adjacent one side of the explosive charge and asecond cylindrically-shaped die surrounding said ferrule adjacent theother side of the explosive charge.

3. A connector adapted to receive a pair of conductors, said connectorhaving a minor diameter in the central section and a major diameter inthe outside sections, a cylindrically-shaped explosive charge on themid-portion of the central section surrounding the outer surfacethereof, and a pair of cylindrical dies disposed about the minordiameter, one on each side of the explosive charge.

4. The device of claim 3 wherein the dies are made of plastic material.

5. The device of claim 3 wherein the dies taper outwardly from a thickersection at the inside edge to a thinner section at the outside edge.

6. The device of claim 3 wherein the central section is solid.

7. A device for connecting stranded cable comprising a tubular metallicmember adapted to receive a length of stranded cable in each endthereof, explosive means surrounding the exterior central section ofsaid tubular member, a pair of die means, each of said die means locatedadjacent said explosive means and adapted to be driven outwardly tocold-forge the tubular member onto the cable, a metal sleeve locatedwithin the tubular member adapted to encompass a strand of said cable,and means for retaining said dies and explosive means on the outersurface of said tubular member.

8. A connector for joining cable comprising: 'a tubular metal member, adie means surrounding the exterior of the tubular metal member, said diemeans comprising a pair of dies having an inner surface conforming tothe outer surface of the tubular member, an explosive member locatedbetween said dies, and a pair of circular metal collars located withinthe tubular member with one of said collars positioned outwardly of oneof said dies and the other collar positioned outwardly of the other ofsaid dies.

No references cited.

DARRELL L. CLAY, Primary Examiner.

1. A CONNECTOR FOR SPLICING CONDUCTORS COMPRISING: A FERRULE ADAPTED TORECEIVE AN ELECTRICAL CONDUCTOR, AN EXPLOSIVE CHARGE SURROUNDING THEOUTER SURFACE OF THE CENTRAL PORTION OF THE FERRULE, MEANS DISPOSED ONSAID FERRULE ACTUATED BY THE EXPLOSIVE CHARGE FOR COLD-FORGING THEFERRULE TO THE CONDUCTOR.